1. Field of the Invention
The present invention generally relates to magnetic storage systems, and more particularly, to suspension assemblies that include a lead routing module.
2. Description of Prior Art
Direct access storage devices (DASD), or disk drives, store information on concentric tracks of one or more rotatable magnetic recording disks. A magnetic head or transducer element is moved from track to track to record and read the desired information. Typically, the magnetic head is positioned on an air bearing slider to form a slider/head assembly which flies above the surface of the disk as the disk rotates. A suspension supports the slider/head assembly and couples the slider/head assembly to a linear or rotary actuator. The combination of the suspension and slider/head assembly may be referred to as a suspension assembly or head gimbal assembly. In general, a rotary actuator moves the slider/head assembly above the disk surface in a generally arcuate path along the radius of the disk surface, whereas a linear actuator moves the slider/head assembly above the disk surface in a generally linear path along the radius of the disk surface.
Many conventional disk drive systems today use a rotary actuator to position a slider/head assembly. For example, FIG. 1 illustrates the translational motion of a slider/head assembly 113 with respect to a disk 112 when positioned by a rotatory actuator 119. The actuator 119 is coupled to slider/head 113 via a suspension 115. During data access operations, disk 112 rotates in the direction indicated by arrow 150 and actuator 119 selectively positions slider/head assembly 113 over disk 112 in response to control signals from a servo electronics (not shown).
The actuator 119 rotates about an axis 127 in the directions indicated by arrows 144. A voice coil 139 is provided at one end of actuator 119 between two pairs of permanent magnets, one of which is shown by reference numeral 137. The outer magnet is attached to the inner side of disk drive system 100. The control signal from the servo control electronics causes a current to flow in voice coil 139 and to generate a magnetic flux. The flux creates force in either direction parallel to the surface of the permanent magnets 137, causing actuator 119 to move in a desired direction. Actuator movement is limited by one or more crash stops 146 that block the range of movement of a protrusion 148. Thus, rotary actuator 119 moves slider/head assembly 113 above the disk surface in a generally arcuate path along the radius of disk 112.
The translational motion of rotary actuator 119 requires in-line mounting of slider/head assembly 113 to suspension 115. For in-line mounting, the head termination pads of the read/write elements located at the trailing end 113A of slider/head assembly 113 are mounted in-line or parallel with suspension 115.
During manufacturing when a disk is tested, one or more testers or test platforms may use a linear actuator, as compared to a rotary actuator, to position a slider/head assembly over the disk. The physical constraints of the test equipment often requires the use of a linear actuator. Unlike rotary actuators, linear actuators require the read/write termination pads located at the trailing end of the slider/head assembly to be mounted orthogonally rather than in-line to the suspension.
FIG. 2 illustrates the relative motion of a suspension assembly with respect to a disk surface when the suspension assembly is positioned by a linear actuator. A slider/head assembly 219 is suspended from a suspension 218. The combination of slider/head assembly 219 and suspension 218 is referred to as a suspension assembly or head gimbal assembly. During data access operations, the suspension assembly is designed to move in a linear translational motion above the surface of a disk 221 as disk 221 is spinning in the direction indicated by arrow 250. The linear translational motion is shown by arrow 230.
As hard disk drives become smaller in size and as their recording track density increases, smaller suspensions are often necessary. Many conventional suspensions are often referred to as “wired suspensions” because individual wires are strung along the suspension and attached to a slider/head assembly. Often the smaller sized suspensions makes it more difficult to string individual wires along the suspension to the head. As a result, there is an industry trend towards integrated lead suspensions in which electrical leads are etched directly into the suspension rather than stringing separate wires.
Integrated lead suspensions generally provide better control of the flying height of a slider/head assembly. However, by integrating the leads into the suspension, the orientation of the wires cannot be changed without redesigning the suspension. It is not an easy task to redesign an integrated lead suspension because it not only needs to be designed with a careful layout of the electrical leads to provide a transmission line for the electrical signals but also needs to provide good mechanical “balance” to properly support the slider/head assembly flying under the influence of air-bearing forces and mechanical forces that occur during high speed access operations. Thus, when the disk testers or platforms require the leads to be configured for orthogonal mounting, a dedicated test suspension may be required for testing, particularly when using an integrated lead suspension. Often it is not economical to design and build the small quantity of these dedicated test suspensions required for testing.
Additionally, as the track densities of hard disk drives increase, it may be advantageous to provide a two-stage servo system that includes both coarse and fine positioning. Generally, the coarse positioning is performed by the conventional actuator such as linear or rotary actuator, and the fine positioning is accomplished by a separate device referred to as a microactuator. The microactuator may be a device coupled between the suspension and slider/head assembly. However, the size and design constraints of a microactuator may not make it feasible to place its termination pads in a location convenient and/or efficient for attachment to the suspension wires.